1. Field of the Invention
The present invention relates to a driving apparatus, especially to a supporting structure of a rotation member such as a pulley.
2. Description of the Related Art
In the conventional electronic equipment such as a reproducing apparatus for a compact disc, a pulley is combined with a loading gear train in order to load or unload a tray for receiving the compact disc. With respect to a mounting method of the pulley, a shaft 2 made of metal is forcedly inserted into a hole formed on a chassis 1 made of synthetic resin as shown in FIG. 8(a) or is fixed to the chassis 1 by means of a fastening member such as a screw. The shaft 2 secured to the chassis 1 in this manner is then inserted into a shaft-receiving portion 4 formed in the center of the pulley 3 as shown in FIG. 8(b). Then, a retainer 6 such as a snap ring so-called "E-ring" is fitted into a ring-shaped groove 5 formed on the head portion of the shaft 2 so that the pulley 3 is rotatably supported on the shaft 2 as shown in FIG. 8(c).
However, in the conventional driving apparatus, the mounting operation of the pulley requires three steps of inserting forcedly the shaft 2 into the hole of the chassis 1 or fixing the shaft 2 to the chassis 1 by means of the screw, mounting the pulley 3 onto the shaft 2 and fitting the snap ring 6 into the groove 5 of the shaft 2. As a result, there are required three constructional components of the shaft 2, the pulley 3 and the snap ring 6.
In addition, the snap ring 6 to be fitted into the groove 5 of the shaft 2 has an inner diameter, which is slightly smaller than the diameter of a portion of the shaft 2, which defines the bottom of the groove 5 of the shaft 2, in order to prevent the pulley 3 from easily coming out from the shaft 2. As a result, an exclusive jig for fitting the snap ring 6 into the groove 5 is required together with many operational steps, thus leading to a complicated assembling operation.